Peptide Database

Human Neutrophil Peptides (HNP-1, HNP-2, HNP-3) · α-defensins

Alpha-defensins are cationic antimicrobial peptides secreted by neutrophils (HNP-1 to 4) and Paneth cells (HD-5, HD-6) in the small intestine. They kill bacteria, fungi, and enveloped viruses through membrane disruption and also function as chemokines, recruiting immune cells and bridging innate and adaptive immunity. Paneth cell alpha-defensins (HD-5, HD-6) play a critical role in shaping intestinal microbiome composition.

Trappin-2 · SKALP

Elafin is an endogenous serine protease inhibitor (serpin-like) peptide produced by epithelial cells at mucosal surfaces. It inhibits neutrophil elastase and proteinase 3, protecting tissues from excessive inflammatory damage, while also exhibiting direct antimicrobial activity against bacteria and fungi. Research focuses on inflammatory bowel disease, cystic fibrosis, ARDS, and vaginal microbiome modulation, where recombinant elafin is in Phase 2 trials.

Cathelicidin · hCAP18/LL-37

LL-37 is the only known human cathelicidin antimicrobial peptide, derived from the C-terminus of hCAP18 protein. It exhibits broad-spectrum antimicrobial activity against bacteria, fungi, and viruses by disrupting microbial membranes. Beyond direct killing, LL-37 modulates inflammation, promotes wound healing, and may have anticancer properties. Research focuses on chronic wound care, infection, and skin disorders like rosacea.

Magainin II

Magainin-2 is a 23-amino-acid cationic antimicrobial peptide (AMP) isolated from the skin of the African clawed frog (Xenopus laevis). It kills bacteria through membrane disruption — forming toroidal pores in bacterial lipid bilayers — while showing low toxicity to mammalian cells due to differences in membrane composition. It is a key model peptide for AMP research and drug design, with a derivative (pexiganan) evaluated in clinical trials for diabetic foot ulcers.